Background

In 1924, geologist Harvey Bassler collected a small frog from the confluence of the Río Santiago and Río Marañón in northwestern Peru. Five years later, after collecting a bizarre frog from the Cordillera del Condor, Bassler collected two more frogs from the Santiago-Marañón junction on his way down the Marañón in a dugout canoe. These specimens were forgotten until being found in a museum collection in 1975, but it wasn’t until Charles Myers’ 1982 paper that these specimens were regarded as distinct species, naming the Cordillera del Condor species Dendrobates mysteriosus and the species from the Santiago D. captivus. Unfortunately, Bassler left no descriptions of live animals, leaving Myers only damaged specimens that had been in alcohol since the start of the Great Depression.

Rainer Schulte traced Bassler’s footsteps to the Cordillera del Condor, and in 1989 documented the first live Dendrobates mysteriosus. However, no such expeditions were ever attempted to rediscover Dendrobates captivus, and understandably so. The type locality as described by Bassler is located in an extremely remote area of Peru, accessible by following the Rio Marañón several days in a boat, only to be greeted by the infamous Pongo de Manseriche. This pongo, or rapid, is formed by a precipitous gorge that cuts through the Cerros de Campanquis, restricting the 750 meter-wide Marañón to a violent 120 meter-wide maelstrom. The peril of reaching the site is exacerbated its inhabitants, the Aguarunas, a sub-tribe of the Shuar Indians, who are most well-known for their curious practice of shrinking the heads of their enemies. These natives have a notorious reputation in Peru of being both fearful and aggressive towards foreigners, especially white ones, who they view as pishtacos (assassins whose primary objective is to extract fats from the bodies of their victims).

The secluded and dangerous nature of the Santiago valley has consequently made it one of the most poorly investigated areas of Peru. Very few biological investigations have been made in the area, and no herpetological surveys, aside from Bassler’s collection of D. captivus, had ever been attempted. For this reason, we decided to go, attempting to find a poison frog that hadn’t been seen by any scientist in 77 years. The expedition was conceived and planned by myself (Evan Twomey), Justin Yeager, Jason Brown, and Manuel Miranda (our contact with the Aguarunas). We were accompanied by Wouter Olthof (a Dutch student), and a small group of filmmakers (Collin Kettell and Richard Sines), an agronomist, and two Peruvian field-hands.

Day 1

Tarapoto – It is night, our truck is packed to the gills with people and supplies. In total there are ten of us leaving from Tarapoto, with the final destination of Rio Santiago, type locality for the elusive Dendrobates captivus. Tonight our only destination is Yurimaguas, a thriving port-town 4 hours north by road, but recent road-assaults have us all on edge. Despite the kidney-busting condition of the road, our excitement levels are through the roof, even though we are a long ways from our final destination. In Yurimaguas we hope to get a boat that will take us the rest of the way, two full days, by river.

Day 2

Yurimaguas – Getting up at 5 am was never so easy. Even though we didn’t get in until midnight, and had to spend the rest of the day on the boat, everyone jumped out of bed, anxious to make progress towards our final destination. Today is San Juan, the biggest holiday of the year for people living in Amazonian Peru. The preferred food on this day is a juane, a delicious but somewhat frightening tamale consisting of rice, hen, and egg, all wrapped in a leaf, so we bought a sack of them for the long ride ahead. Our plan of action was to descend the Rio Huallaga until the junction of the Marañón, whereupon we would make a westward turn to approach the Pongo de Manseriche from the east. After a long morning in the boat, we finally made it to the confluence of the Huallaga and the Marañón. The Rio Marañón is the primary headwater of the Amazon river, flowing briskly away from the Andes, and finally slugging its way across the lowlands to pick up the Rio Huallaga, and finally the Rio Ucayali, where the Amazon officially begins. From this point on, we would be fighting the current, so our progress would be substantially slowed. By nightfall, we only made it as far as San Lorenzo, a bustling town near the mouth of the Rio Pastaza. Here we replenished our enthusiasm with some more juanes and beer.

Day 3

San Lorenzo – Another day in the boat was ahead of us, but the possibility that we might make it in the field today had everybody anxious to get going. After fueling up, we continued our ascent of the Marañón. Before long, a chain of mountains rose out of the horizon: we were looking at the Cerros de Campanquis, the Andean front-range that effectively isolates the Santiago valley from the rest of Amazonia. By lunchtime we had made it to Sarameriza, an isolated but lively town a few hours downriver of the Pongo de Manseriche. After Sarameriza there were no more towns with gas stations, so we had to carry enough gasoline to last our boat for the next four days. Our boat driver had a change of heart – he did not now feel comfortable navigating the Pongo de Manseriche, having only done it once, several years back. Being in a town so close to the Pongo, we were able to find a young man with extensive experience navigating the area, being comfortable with both the Pongo de Manseriche and the natives living above it. After leaving Sarameriza and continuing up the Marañón, the excitement in the boat reached an all-time high. The Cerros de Campanquis rose higher and higher above the horizon, until they appeared as a massive green wall of virgin rainforest. By mid-afternoon, we had reached the tiny village of Borja, an old missionary station situated immediately under the shadow of the Pongo de Manseriche. This would be our last stop before the Pongo and our last stop before entering Aguaruna territory.

As we left Borja and made our way to the mouth of the Pongo, we realized that the peaceful lower Marañón had finally given way to a monster: a narrow canyon with powerful currents, whirlpools, and huge rocks. We were finally in a position to see the bottom of the Pongo de Manseriche, and it looked like someone had taken a huge axe and smashed the Cerros de Campanquis, leaving only a small sliver for a pass. To navigate the Pongo, one must pass through two treacherous straits, the first being where the Marañón smashes into a massive crag, forming an enormous maelstrom, locally known as the huaccanqui (literally, “you’ll cry” in Aguaruna). Passing this strait, one is then faced with a second, more perilous section know as the asnahuaccanqui (“you’ll cry until you rot”), a 100-meter stretch of whitewater riddled with boulders and whirlpools. As we made our way slowly and carefully up the Pongo, it felt like we were entering another world. The rocks were filled with strange birds (reminiscent of blue-footed boobies) and orchids, and long strands of moss hung from the trees and cliffs due to the constantly misty conditions inside the gorge.

When we asked our guide where we were going to camp, we thought he was joking when he told us we would make base camp inside the Pongo itself. However, after making it through the roughest spots, we were pleased to find a beautiful sand beach, surrounded by cliffs and mountains, the Marañón roaring past. Stopping here, we quickly unloaded the boat – there was still the chance at getting in the field for maybe an hour.

After only a few minutes in the forest, we spotted a small red frog on the forest floor, which Justin Yeager, having experience with Ecuadorian frogs, identified as Epipedobates parvulus. Further searching turned up more of this species, but the limited daylight cut short our search. The search for Dendrobates captivus would have to wait until tomorrow.

Meanwhile, our guide Manuel Miranda, along with an Aguaruna translator, were above the Pongo negotiating with the Aguarunas for us to enter their land the following morning. They returned later that night, several hours later than anyone anticipated. When we asked how negotiations went with the Aguarunas; a somber Manuel replied “Not good.”

Part two: Frogs and Indians

Day 4

Aguaruna village – We are sitting in a small thatched hut, surrounded by roughly 60 people from the Aguaruna tribe. The town leader has called a meeting to have a community discussion of our business there, and whether or not we should be allowed to enter their land will depend on their decision. Being surrounded by an entire village of wary natives is not a feeling any of us are soon going to forget. Many times, the discussions, which were conducted entirely in the Aguaruna language, would rise to turmoil, and people began to shout and point at us. We could see in the eyes of our translator that negotiations were not going well; no word-for-word translation was needed. Below is an excerpt from Jason Brown’s journal entry of the meeting with the Aguarunas:

“An hour after of entering the Aguarunas’ village, people began to yell and scream in Aguaruna. Everyone in our party’s skin turned a light shade of green, as we could tell things were not as controlled as we had hoped. Moments later, people began to clap and yell; this caused others to stand and yell. Everyone in our party looked on in terrified silence; fortunately after ten minutes, the chaos was subdued by a few elder Aguarunas when they forced 3 or 4 drunks to leave that had been getting aggressive. What exactly happened in those minutes, we will never know. One of the translators told us that one of the Indians stood up and proposed that they kill us, however few people responded. To muster support he began to clap, however this enraged many of the other Aguarunas whom violently opposed this proposal (which was good for us, but this is when we started to get scared). Again, we will never know what was said, but whatever was said was taken very seriously by all the members of the tribe and everyone voiced their opinion. This was one of the most terrifying moments of my life.”

Fortunately, our guides were able to calm the villagers down, and after much negotiating, the Aguarunas had agreed to let us in. We were assigned two guides for the rest of the day. As we hiked into their forest, we asked them if they had seen a small frog with spots on the back. They said they had, but since no photos existed of this frog we had no idea if we were even describing the right frog.

The most unbelievable feeling in the world is to stand at the edge of an unexplored rainforest, not knowing what lies inside. Only a handful of scientists had ever entered this region, and to our knowledge we were the first herpetologists to have ever been here. Somewhere in this forest was a tiny frog that had not been seen in 77 years, and had never been documented in life. We began to search along a streambed; the habitat looked promising. Jason Brown and I split off from the group to search along a smaller creek, but before long, we heard Justin Yeager yelling in the distance, “Captivus! Captivus!”. Jason and I came barreling down the creek, bristling with excitement, to find Justin with our guides looking into a small bucket. Peering in, we screamed out in excitement: inside was a Dendrobates captivus, and it was more spectacular than any of us would have ever imagined. This first frog was caught by one of our guides, who showed it to Justin. Immediately he realized what it was; a small poison frog with bright red spots on the back, so he called us down.

The following few hours were exhilarating. D. captivus were quite common. We were able to record their calls, observe courting behavior and tadpole transport, and document color and pattern variation. Our Aguaruna guides were amused. Here was a group of foreigners that had traveled several hundred miles to find a tiny frog, a frog which the natives had all seen many times before when hunting in the forest.

Later that afternoon we returned to the Aguaruna village for lunch, and eventually returned to our base camp, everyone satisfied and relieved that the expedition was a success. But we still had a lot of work to do. The Santiago river remained unexplored, as did the Cerros de Campanquis to the east. But tonight we celebrated the rediscovery of Dendrobates captivus, and slept contentedly in our hammocks.

Day 5

Rio Santiago – As we ascended the Santiago, the morning sky looked ominous. Our goal for the day was to try to document more populations of D. captivus along both sides of the Santiago, but it looked like our search would be compromised by the rain, which was now falling in sheets. This area posed no threat to us; we were now in the territory of the Huambisas, a rival tribe of the Aguarunas. Fortunately, the Huambisas were friendly and accommodating, and only had an interest in fighting other Aguarunas, usually over women or land. In fact, one of the Huambisa villagers informed us that there had been wars between the two tribes as recently as a couple years ago, but the Peruvian government had now been intervening to stop intertribal combat.

We spent much of the day inside a Huambisa house, learning of their culture and way of life. We were offered masato, a drink made from cassava which has been chewed by the Huambisa women and spat into a vessel to ferment. For the natives, this drink is a fundamental source of nutrition, and since refusal would be insulting, we reluctantly tasted it. As we sat with the Huambisas, looking at the nearby mountains, we realized that we had to cross them. To our knowledge, no scientist had ever been in these mountains: the potential for new discoveries was high. We asked our host if it was possible to cross the Cerros de Campanquis on foot; he informed us that it was, but few people made that trek anymore since the trails were very poor and it was easy to get lost. He did, however, suggest two guides, both of whom claimed to have walked the trail recently. According to them, it would take less than half a day to reach Borja. Our plan was set. We would set out early the next morning and try to traverse the Cerros de Campanquis.

Day 6

Base camp – The rain continued all night, dripping into our hammocks, making it difficult to sleep. When we informed our party of the plan to cross the mountains, few wanted to join us. Only a small group of us (Jason, Wouter, and I) had the desire to attempt this hike. The rest of our party would spend the day searching around the Pongo, and planned to meet us in Borja later that afternoon.

Since our guides told us the hike was possible to do in one day, we left behind our hammocks, bringing only some crackers and a water filter. Our plan was to leave from a village on the Santiago, striking east towards the mountains and Borja on the other side. Making our way across the Santiago plain to the mountains proved to be much more time consuming that anyone thought. The trails were worse than our guides remembered, and the rains from the day before had the rivers in flood stage. After a frustrating zigzag across multiple rivers, we made it finally to the base of the mountains, but it was already mid-afternoon. Ascending the mountains proved to be just as difficult. The small trail quickly narrowed to a game path, which had us perpetually hunched over to avoid the overhanging vegetation. Furthermore, frogs were nowhere to be found. Even Epipedobates parvulus, which was common in the lowlands, began to disappear around 500 meters elevation.

The forest on the top of the Cerros de Campanquis is entirely untouched by humans. Our guides now informed us that the last time anyone even set foot up here was 6 months ago, and that they had not walked this trail in over 20 years. The climb was slow, and we did not summit until 5 pm. Night was only 2 hours away, and we still had the entire descent in front of us. As we made our way down, the wet forest began to grow dark and cool. We quickly realized that there would be no way to make it out of the mountains before dark. Fortunately, we all had flashlights, so we continued to make our way down late into the night. The entire descent had us following the spine of a sheer ridge, and stumbling over strange volcanic rocks resembling jagged coral. Being on top of a ridge, water was nowhere to be found. We followed our guides for hours, frequently losing the trail, then backtracking, walking in circles, and the whole time in a direction that would lead us far to the north of Borja. Reaching town tonight was hopeless. Presently we had a bigger concern, which was water. We had not passed a stream since about an hour before the summit, and it was currently midnight.

Day 7

Cerros de Campanquis – Jason, Wouter, and I breathed a huge sigh of relief upon reaching a small stream, but after quenching our thirst, we came to the realization that we could go no further tonight. Our guides came to the same conclusion, so we found a dry spot on the forest floor, covered it with large leaves, and lay down for the night. Sleeping on the forest floor with nothing but the clothes on your back is quite uncomfortable. There are a multitude of creatures waiting to chew on you – bees, ants, mosquitoes – but we just had to deal with them until it was light enough to proceed. We got about 45 minutes of sleep the entire night. Our guides, perhaps feeling guilty about misleading us, spent the entire night trying to find the trail again. Below is another excerpt from Jason’s journal:

“The bed was terrible. There were twigs and branches sticking in my back. Soon after lying down, some strange animal began to rustle and hiss in the tree tops. I have no clue what it was, but when it started I was glad to look over and see Wouter sleeping on his stomach, face in the dirt. The noise continued on and off throughout the night. Because we had been hiking all day we were covered in sweat and the insects loved it. I was covered with strange mosquitoes and ants. Sometime around 3:00AM my right eye grew warm and began to pus. By morning my eye was red and infected and was tearing profusely. Around 5:30 AM we all got up and began hiking again as the sun crawled over the horizon. Sometime in the night our guides found the correct trail.”

We still were in the mountains, but after a few hours more of perseverance, the trail began to widen. We slowly approached the lowlands, and the human influence was noticeable again. We ended up hiking to a village several kilometers down river of Borja, but fortunately a Peruvian with a boat offered to take us back upriver to rejoin our party.

The other members of our team were relieved to find us alive, albeit exhausted. Though we did not find any more D. captivus, we were glad to learn that the others found several. Lunch in Borja was delicious and miraculously they had cold beer, which brought our vitality back in no time. Dendrobates captivus found, our mission was a success. After resting a bit, we all agreed it was time to make our way down the Marañón, back home.

Day 8

San Lorenzo – What a great town. We finally got to shower for the first time on the trip. Plus, San Lorenzo has some great food and even a pool hall. We decided to spend the day around San Lorenzo, getting into the field a bit on both sides of the Marañón, but didn’t find much. Dinner was cheerful and everyone appreciated a solid night’s rest.

Day 9

San Lorenzo – Today we were hoping to make it back to Tarapoto. We left San Lorenzo early, and after an entire day in the boat, made it to Yurimaguas by dinner time. After a long drive along some terrible roads, we finally made it back to Tarapoto, glad to be back safely.

Summary

The expedition was better than anyone would have predicted. Not only did we all make it out safely, but Dendrobates captivus turned out to be a little gem with some interesting behaviors. We thought this species might be brown with white or yellow spots, no one was predicting black with red spots and yellow flash marks. Overall, we surveyed several sites around the Pongo de Manseriche, and although there are undoubtedly more discoveries to be made there, we felt that this expedition was a good initial survey of an unknown area.

Though the Santiago valley is relatively undisturbed, nearby oil drilling and road construction may quickly place the area at risk for deforestation. We suspect that D. captivus may be restricted to the Santiago valley, and as such would have a very small range, thus being at elevated risk of habitat destruction or illegal collection for the pet trade.

-Evan Twomey
March 25th, 2007

Holotypes of Dendrobates mysteriosus (left), and D. captivus (right). These specimens were collected by Bassler in the 1920s and were the only existing material for these species at the time of their description in 1982. (Myers 1982)

Map of the region. Our expedition followed the Marañón west to the mouth of the Rio Santiago.

Pongo de Manseriche, drawing from the late 1800s.

Sunset on road near Tarapoto. (Photo: Evan Twomey)

Cramped boat for 2 days. (Photo: Jason Brown)

Headwaters of the Amazon. (Photo: Wouter Olthof)

The children of Sarameriza wishing us well on our travels. (Photo: Jason Brown)

Final approach of the Cerros de Campanquis. (Photo: Wouter Olthof)

Entering the Pongo de Manseriche. (Photo: Wouter Olthof)

Passing the asnahuaccanqui, most dangerous section of the Pongo de Manseriche. The driver made us get out and hike alongside for safety reasons. (Photo: Evan Twomey)

A sight few have seen: the upper Pongo de Manseriche, June 26th, 2006. (Photo: Evan Twomey)

Base camp in the Pongo. (Photo: Evan Twomey)

First night in camp. (Photo: Wouter Olthof)

Rainbow boa (Epicrates cenchria) caught near camp. For most of us, this was the first wild rainbow boa we had ever seen. (Photo: Wouter Olthof)

Rio Marañón above Pongo de Manseriche, near the mouth of the Rio Santiago. (Photo: Wouter Olthof)

Dendrobates captivus, at last! Last seen in 1929, rediscovered in 2006. (Photo: Jason Brown)